基于CSAPF的磁铁电源纹波抑制研究

加速器系统中由于大量非线性器件的存在产生了大量纹波,严重影响加速器磁场对粒子运动轨迹的控制.为实现对加速器直流电源纹波的抑制,相关研究主要集中在用电压型有源电力滤波器降低直流电源纹波,但该方法存在抑制精度不足、响应延时、开关设备损耗较大等问题.针对以上问题,本文比较了电流型和电压型有源电力滤波器的主电路拓扑结构,研究了...     

Two New Phenolic Glycosides with Lactone Structural Units from Leaves of Ardisia crenata Sims with Antibacterial and Anti-Inflammatory Activities

Two new lactones, named Ardisicreolides A–B (1–2), together with four known flavonoids, Quercetin (3), Myricetrin (4), Quercitrin (5), Tamarixetin 3-O-rhamnoside (6), were isolated from the ethyl acetate portion of 70% ethanol extracts of dried leaves from Ardisia crenata Sims. These compounds were identified from Ardisia crenata Sims for the first time. The structures of 1–6 were elucidated according to 1D and 2D-NMR methods and together with the published literature. All of the isolated compounds were evaluated for in vitro anti-microbial effect against Escherichia coli, Pseudomonas aeuroginosa, Enterococcus faecalis, Proteus vulgaris, Staphylococcus aureus, and Bacillus subtilis. In addition, compounds 1–2 were assessed for anti-inflammatory activity by acting on LPS-induced RAW 264.7 macrophage cells in vitro. The results showed that only compound 2 exhibited moderate antibacterial activity on Bacillus subtilis. Moreover, compounds 1 and 2 were found to significantly inhibit the production of nitric oxide (NO) and reduce the release of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-4 (IL-4), and interleukin-10 (IL-10) in LPS-induced RAW 264.7 macrophage cells. The present data suggest that lactones from the leaves of A. crenata Sims might be used as a potential source of natural anti-inflammatory agents.     

3.0T 磁共振血管成像诊断颅内动脉成窗畸形的临床应用

目的 探讨3.0T 磁共振血管成像（MRA）诊断颅内动脉成窗畸形（FIA）的临床应用价值，了解FIA 的MRA 表现、好发部位以及临床特征。方法 回顾性分析2012 年4 月至2014年12 月共78例FIA 患者的血管畸形好发部位、类型及其合并其它颅内血管性病变的情况。78例患者均行MRA 扫描，再将原始图像经AW4.5 工作站采用最小密度投影（MIP）及三维容积重建（VR）两种方法进行血管重组，并对血管图像进行后处理。结果78例FIA 患者中，单发61 例，多发17 例，共计95 处。其中61 例单发病例中位于基底动脉15 例，位于前交通动脉区13 例，位于大脑前动脉26 例，位于大脑中动脉5例，位于大脑后动脉2 例；17 例多发病例中，位于基底动脉及左大脑前动脉6例，位于左椎动脉颅内段及左大脑前动脉7 例，位于基底动脉及前交通动脉4 例。78 例患者中合并其它颅内血管性病变者占83.3%（65/78），双侧动脉对比一侧优势者36 例，伴动静脉畸形（AVM）1 例，永存三叉动脉3例，大脑前动脉A1 段缺失16 例，血管狭窄9例。结论 3.0T MRA 能清楚显示FIA 的位置、形态及合并颅内其它血管病变的情况，是诊断FIA 的首选、有效、无创的影像检查方法。     

AB5型非化学计量贮氢合金电极过程动力学研究

为了探明取代元素对非化学计量AB5型贮氢合金氢化物电极充放电性能的影响因素,对LaNi5.15,La(NiSn)5.14,La(NiSnCo)5.12,La(NiSnMn)5.12和La(NiSnCoMnAl)5.10开展了电极过程动力学的研究。采用线性极化的方法,控制电极过电势小于5mV,测量出不同荷电容量下电化学反应的交换电流密度。电极在满充电状态下i0并非最大,当电极部分放电后该值达到最大。对Co,Mn或Al部分取代形成的非化学计量多元贮氢合金的交换电流密度研究表明,Co有利于提高i0,而Mn和Al不利于提高i0。当氢化物电极中贮氢容量较小时,电极反应的交换电流密度与电极中贮氢容量存在对数值的线性关系。对于具有几乎一致的电极反应电子传递系数β的La(NiSn)5.14,La(NiSnCo)5.12,La(NiSnMn)5.12,La(NiSnCoMnAl)5.10氢化物电极,造成交换电流密度差异来源于热力学吸附平衡常数K0与反应活化能W0。含Al贮氢合金K0较低,这是影响交换电流密度的主要因素。对K0值接近的3种贮氢合金La(NiSn)5.14,La(NiSnCo)5.12,La(NiSnMn)5.12,活化能W0是造成交换电流密度不同的主要原因。     

Synthesis of substituted oxa- and aza[3.2.1] and [4.3.1]bicyclics via an unprecedented molybdenum-mediated 1,5-"Michael-type" reaction

The direct internal nucleophilic functionalization of a pi-bound carbon of neutral TpMo(CO)2(5-oxo-eta3-pyranyl) and TpMo(CO)2(5-oxo-eta3-pyridinyl) complexes by enolates represents a new reaction profile for neutral TpMo(CO)2(eta3-allyl) complexes. This Mo-mediated "1,5-Michael reaction" proceeds in good to excellent yields and provides, after demetalation, a new and efficient synthetic approach to oxa- and aza[3.2.1]bicyclics of high enantiomeric purity.     

A facile aminocyclization for the synthesis of pyrrolidine and piperidine derivatives

Bromination of an isolated double bond followed by aminocyclization furnishes a highly stereoselective protocol for the intramolecular formation of pyrrolidine and piperidine ring containing subunits that are presented in numerous biologically active natural products.     

1-苯基-3-甲基-4-苯甲酰基-吡唑啉酮-5(HPMBP)的金属离子配合物的结构研究——Ⅰ.HPMBP及其配合物Cu(PMBP)_2的晶体结构

本文研究了Cu(PMBP)_2和HPMBP的单晶体结构,晶体学参数为:(1)HPMBP,C_(17)H_(14)0_2N_2,M=278.31,单斜晶系,空间群P2_1/a,a=11.406(5),b=9.087(1),c=13.467(3)(?),β=90.76(3)°,V=1395.7(?)~3,Z=4,D_c=1.324g cm~(-3),μ=0.95cm~(-1).(2)Cu(PMBP)_2,C_(34)H_(26)O_4N_4Cu,M=618.16,单斜晶系,空间群P_2_1/c,a=6.809(3),b=23.722(8),c=9.102(3)(?),β=108.94(4)°,V=1390.7(?)~3,Z=2,D_c=1.476g cm~(-3) μ=8.67cm~(-1).结果表明,HPMBP具有烯醇式结构,其中两个给体氧原子处于有利于形成六元螯合环的几何位置;在配合物Cu(PMBP)_2中,Cu原子为对称中心,两个配体中的四个氧原子形成以Cu为中心的近似平面正方形的配位结构,Cu-O距离分别为1.906和1.896(?).     

Enhanced emission efficiency and excited state lifetime due to restricted intramolecular motion in silole aggregates

The aggregation-induced emission (AIE) properties of 1,1,2,3,4,5-hexaphenylsilole (HPS) and poly{11-[(1,2,3,4,5-pentaphenylsilolyl)oxy]-1-phenyl-1-undecyne} (PS9PA) were studied by time-resolved fluorescence technique. The enhanced fluorescence and long fluorescent lifetime were obtained for the sample in an aggregate state as compared to the sample in solution. The time-decay of fluorescence of HPS and PS9PA in high viscosity solvents and low-temperature glasses has also been measured in detail to further investigate the possible mechanism for AIE. Enhanced light emission and long fluorescence lifetime were detected for both HPS and PS9PA in the solution-thickening and -cooling experiments. These results provided direct evidence that the enhanced photoluminescence (PL) efficiency is due to restricted intramolecular motion, which ascribes AIE to the deactivation of nonradiative decay caused by restricted torsional motions of the molecules in the solid state or aggregate form.